In recent years, demands for high performance and low cost of filtering media have been increased in the field of filters for air conditioning, air conditioners, and automobiles, and many investigations on filtering media for filters which simultaneously satisfy both dust-removing capability and deodorizing capability have been made. Generally, in order to provide deodorizing capability, methods for making sheets by using granular or fibrous adsorbents and adhesives have often been employed and, for example, adsorbing filtering media have been developed which are obtained by spraying a mixture of a granular adsorbent and a granular adhesive between base materials and heat-bonding the resulting materials (e.g., Patent Document 1). However, because of weak adhesive strength, the adsorbing filtering media have problems of dropping of the adsorbent and lowering of the rigidity.
In order to solve such problems, there is a method for increasing the mixing ratio of an adhesive, but the method causes decrease in deodorizing capability due to the coating on the adsorbent surface or increase in pressure loss. Patent Document 2 discloses that a needle-punched nonwoven fabric and an adsorbing layer are adjacent, to each other and the fluff of the needle-punched nonwoven fabric enters in the adsorbing layer to increase the adhesive strength due to an anchor effect. However, in the case where the fluff of the filtering medium surface is noticeable, the appearance grade is undesirably deteriorated and the rigidity is also insufficient.